Apparatus for rolling metal powder



Aug. 8, 1961 H. FRITSCH APPARATUS FOR ROLLING METAL POWDER Filed July 28. 1954 INVENTOR.

Hermann Frirsch BYMM ATTORNEYSv United States Patent ice y 2,994,917 APPARATUS FOR. ROLLING METAL POWDER Hermann Fritsch, Dusseldorf, Germany, assignor, by

Thisinvention relates to an apparatus for converting metal powder into wrought metal shapes, such as metal sheets, strips, rods, wirestand the like.

Metal powder has heretofore been rolled into wrought metal shapes by tightly compressing. the powder between oppositely disposed, laterally spaced pressure. rolls. The wroughtmetal shapes thus produced are invariably then sintered in a suitable furnace to produce metal products having a substantially coherent. structure. The loose metal powder, which is introduced into the roll gapbetween the spaced rollsby means of a suitable hopper, is

compacted. by the rollsinto a dense mass in which the individual particles; of metal powder cling together with surprising tenacity; Whenmetal powder is rolled in this manner, it is essential that the pressure rolls have adiameter many times larger than the thickness of the strip of compressed metal powder produced by the rolls,

Because of the. relationship between the diameter of the rollsand the thickness of the strip that can be compacted by such rolls, rolling apparatus adapted to produce a: compressed: metal strip lacksflexibilit'y with regard to the thicknessof the strip that can be produced thereby. Moreover, di-fliculty is experienced in producing a strip of. compressed metal powder having uniform density and surface, due to the problems encountered in feeding loose: metal powder directly to? the rolls and having; the. rolls draw this looser powder uniformly and smoothly down intothe roll gap to produce the compressed metal powderstrip.

I have now found that, by precompacting loose metal powder intoa lightly precompressed strip of metal powder prior to introducing the metal powder into the: roll gap defined by the-pressurerolls, I can producea compressed. powdered metal strip uniform" in density and surface, and in a wider range of thickness of strip than has heretofore been produced-by a pair of pressure rolls of a; given diameter. Moreover, I have devised a novel'apparatus for producing wrought metal shapeswhich includes means for lightly precompressing the loose metal powder intoa strip unsuitable for sintering, andmeans for tightly compressing the strip' thus. produced into a strip suitable for sintering'into' a substantially coherent strip ofm'etal'. The; apparatus of thepresent invention comprises com pactor means for compacting loose'metal powder into a lightly precompressed? strip, andxapani of oppositely disposedlaterallyspacedtpressure rolls defining a roll gap the widthof' which isless .tha-n'tlie thickness of the lightly precompressed-strip of rnetal: powder prepared by the compactor means: The compactor: means advantageously comprises atv leastone: pair of convergent compactor elemerits; each 3 of whichi is: disposed" at. an acute angle 1 tothe common ofsthepairof elementswhereby the.

elements define betweenflthem a truncated V.-shaped passageway adapted; to: compress loose "metal powder fed} ipto; -t,he-wide:e'nd 1of the 'passageway into a lightl y precompressed :st ip-w of powder :tliat is "discharged from the narrow-end ofithesaideV=shapedrpassageway m ce may chad toethedrawings'iniwhichz l' i EIGU I l-lSLEIasGlIfilllQfiCfViCW of an embodiment of I yention imwhieh the-convergent compactor. elements cgorriprisee oppositelyudisposed reciprocating plates; and

a; Foraa'moregdetailededescription eithe -invention,refera schematicviewot another'emBod-iment 2,994,917 Patented Aug, 8, 1961 of. my invention in which the compactor elements comprise a pair of link belts mounted. for convergent travel.

In the embodiment of my apparatus shown in FIG- URE 1, ahopper 10- feeds loose metal powder 11 into the space between apair of oppositely disposed laterally spaced convergent compactor elements 12.- In the apparatus shown, two pairs of compactor elements 12 in axial alignment: comprise the compactor means of my invention. Each compactor. element 12 is disposed at a slightly acute angle with respect to the common axis of the pair of elements so that the pair defines a truncated V-shaped passageway. The common axisof the pair of elements is the axis of symmetry lying between the pair.

The compactor elements 12 of each pair are movable laterally with respect to each other and means 13 are provided for moving these compactor elements in synchronization alternately toward and then away from each other. The amount of lateral movement of the compactor elements 12 is regulated so that the loose metal powder 11 introduced into the passageway between the compactor elements islightly compressed by these compactor elements when they move toward each other. The compacting pressure exerted by the compactor elements on the loose metal powder necessary to form a lightly precompressed metal powder strip will depend upon the kind, the degree of subdivision and the cohesive properties strip of metal powder should have suflicientmechanical strength to retain its form while being introduced into the pressure rolls, but should not beso tightly compressed as to be suitable for directsintering into a substantially coherent strip of metal.

The lightly precompressed metal powder emerging from the discharge end of the. V shaped passageway defined by the compactor elements 12 is introduced into the rollgap defined by a pair of oppositely disposed, laterally spaced pressure rolls 15;. Thediameter. of each of these pressure rolls is many times larger than the width of the strip of metal powder introducedthereinto; The width of the roll gap defined by the. pressure rolls 15 is appreciably less than the thickness of the lightly precom pressed strip of powder which is, of course, determined by the lateral spacing of the compactor elements-12 at: the discharge end of. the passageway defined thereby; Thu-s, the'lightly precompressed strip of metal powder produced by the convergent compactor elements 12; is: tightly compressed by the pressure rolls 1 5 into a strip- 16 suitable for sintering in a sintering furnace 17.- i

The sintering furnace 17 sinters the tightly compressed strip of metal powder to form a substantially coherent strip of metal 18 suitable for many purposes, including subsequent cold rolling to reduce the sintered strip'to a solid bar, rod, or wire of the parent metal. In the apparatus shown in FIG. 1, the sintering furnace 17 is'ofiset pair of elements so that a truncatedv shaped passageway is defined by'the adjacent outer surfaces of the links in the link" belts21. The outersurfaces of the links inthe link belt 21 form substantially continuous'lpressure sur faces adapted to compress loose metal powder received i'n tlie 'V-shaped passageway into a lightly precompacted metal powder strip. Drive means 23 are provided for rotating the wheels 22 so that the adjacent surfaces of the link belts 21 will move downwardly toward the narrow end of the passageway defined by said adjacent surfaces at the same rate of speed, thus insuring uniform compaction of the powdered metal.

The wheels 22 on which the link belts 21 are mounted are advantageously laterally adjustable so that the width of the wide entrance and the narrow exit end of the convergent V-shaped passageway may be adjusted as circumstances warrant. The under sides of the link belts extending between the wheels 22 are provided with support members 24 adapted to support the pressure surfaces of the link belts employed in the compressing operation. The links of the link belts 21 advantageously overlap each other slightly to provide the pressure surfaces of the link belts with a saw-tooth configuration that facilitates the precompression of the metal powder by drawing the loose powder evenly downwardly into the converging passageway defined by the link belts of the compactor elements 20.

The convergent compactor elements 20 of my apparatus lightly precompress the loose metal powder 11 into a strip having moderate mechanical strength and not suflicient density to be successfully sintered into a substantially coherent metal strip. The lightly compressed strip of metal powder discharged from the compactor elements 20 is introduced into the roll gap of a pair of oppositely disposed, laterally spaced pressure rolls 15. The width of the roll gap defined by the pressure rolls 15 is appreoiably less than the thickness of the lightly precompressed strip of metal powder introduced thereinto. The width of the precompressed strip of metal powder, of course, is determined by the lateral spacing of the convergent compactor elements at the narrow end of the V-shaped passageway defined thereby. The pressure rolls thus further compress the lightly precompressed strip of metal powder into a dense strip of tightly compressed powdered metal 16 suitable for sintering in a sintering furnace (not shown).

Advantageously, a strip of elastically deformable material is introduced between the pressure rolls 15 and the metal powder being compressed thereby in the manner described in the copending application of Gerhard Naeser, Serial No. 417,322, filed March 19, 1954, and now abandoned. By the use of such an elastically deformable material in rolling metal powders, undesirable 'sidewise spreading of the compressed metal strip is avoided as described in the aforesaid application. I The apparatus of the present invention may be used to compress many different metal powders, such as copper, iron, lead, nickel, cobalt, and the like, into wrought metal shapes. Various mixtures of metal powder may also be used to produce metal alloys.

Although various changes and modifications may be made in the particular constructions illustrated and described without departing from my invention, I presently prefer to employ the embodiment of my invention shown in FIGURE 2.

I claim: 1. Apparatus for converting metal powder into wrought metal shapes comprising at least one pair of oppositely disposed laterally spaced convergent vertical compactor elements, each of said compactor elements comprising an endless link belt mounted to travel about a pair of supporting wheels, the adjacent outer surfaces of said link belts forming substantially continuous pressure surfaces inclined at an acute angle to the common axis of said pair of compactor elements whereby said adjacent pres sure surfaces define a truncated V-shaped passageway, means for moving said link belts at the same rate of speed and in opposite directions so that said adjacent pressure surfaces travel uniformly toward the narrow end of the truncated V-shaped passageway defined by said compactor elements forcornpactin'g loose nietal pow- .4 der into a lightly precompressed strip of metal powder having sufiicient mechanical strength to retain its form while being introduced into a pair of pressure rolls but not of a suflicient density to be successfully sintered into a substantially coherent metal strip, a metal power feed hopper adapted to introduce loose metal powder into the wide end of said truncated V-shaped passageway, and a pair of oppositely disposed laterally spaced pressure rolls having the axis of the rolls disposed in a horizontal plane defining a roll gap the width of which is appreciably less than the width of the narrow end of the passageway defined by said compactor elements for compacting the lightly precompressed strip of metal into a compressed strip of metal of a sufficient density to be successfully sintered into a substantially coherent metal strip, said pressure rolls being disposed adjacent the narrow end of said compactor elements with the roll gap in alignment with the truncated V-shaped passageway defined by said compactor elements.

2. Apparatus according to claim 1 in which one edge of each link in said link belt overlaps one of the adjoining links while the opposite edge of said link is overlapped by the other of the adjoining links in said link belt.

3. Apparatus according to claim 1 in which the pair' of compactor elements are laterally adjustable with respect to each other whereby the width of the truncated V-shaped passageway defined by said compactor elements may be adjusted.

4. Apparatus for converting metal powder into wrought metal shapes comprising at least one pair of oppositely disposed laterally spaced vertical compactor elements, each of said compactor elements being inclined at an acute angle to the common axis of said pair of compactor elements whereby said pair of elements define a truncated V-shaped passageway, means for moving said pair of compactor elements in a reciprocating lateral path of travel alternately toward and away from each other for compacting loose metal powder into a lightly precompressed strip of metal powder having suflicient mechanical strength to retain its form while being introduced into a pair of pressure rolls but not of a suflicient density to be successfully sintered into a substantially coherent metal strip, a metal powder feed hopper adapted to introduce loose metal powder into the wide end of said truncated V- shaped passageway, and a pair of oppositely disposed laterally spaced pressure rolls having the axis of the rolls disposed in a horizontal plane defining a roll gap the width of which is appreciably less than the width of the narrow end of said truncated V-shaped passageway defined by said pair of compactor elements, said pressure rollsbeing disposed adjacent said narrow end of said pair of compactor elements with said roll gap in alignment with the truncated V-shaped passageway defined by said pair of compactor elements for compacting the lightly precompressed strip of metal into a compressed strip of metal of a sufiicient density to be successfully sintered into a substantially coherent metal strip.

- 5. Apparatus for converting metal powder into wrought metal shape comprising at least one pair of oppositely disposed laterally spaced convergent vertical compactor elements defining a truncated V-shaped' passageway for compacting loose metal powder into a lightly precompressed stnip of metal powder having sufiicient mechanical strength to retain its form while being introduced into a pair of pressure rolls but not of a sufiicient density to be successfully sintered into a substantially coherent metal strip, a metal powder feed hopper adapted. to introduce loose metal powder into the wide end of said truncated V-shaped passageway, and a pair of oppositely disposed laterally spaced pressure rolls having the axis of the rolls disposed in a horizontal plane defining a roll' gap the width of which: is 'appreciablyless than the closest distance separating said convergent compactor elementsdisposed adjacent and .in alignment withthe narrow end of said truncated V-shaped passageway definedby said compactor elements for compacting the lightly precom- References Cited in the file of this patent UNITED STATES PATENTS Grubman Jan. 7, 1936 Loomis Mar. 30, 1937 6 Marvin Feb. 15, 1944 Adams June 17, 1947 Fischbein July 15, 1952 Leavenwoxth Sept. 15, 1953 Upton Nov. 3, 1953 Leng Sept. 28, 1954 Herres et a1 May 24, 1955 Dickey Sept. 13, 1955 Hjulian Mar. 12, 1957 

